Engine Idle High: 1250 RPM, Low Power, 6 Errors

Hello everyone,

I own a VW Passat, model year 1994, with a 1.9 TDI engine and a 1Z engine code.

It suddenly idles at 1250 RPM and has power loss throughout the entire RPM range.
I was able to read the following error codes from the control unit.

00527 Sensor for intake air temperature (g27) 30-00: Open circuit/Short circuit to positive.

00777 Accelerator pedal position (g79) 27-00, implausible signal.

00522 Coolant temperature sensor (g62).

00539 Fuel temperature sensor (G81) - Open circuit/Short circuit after positive terminal.

00741 Brake pedal monitoring - 27-00, implausible signal.

00553 Air mass sensor (g70) 28-00 Short circuit to positive.

The error message about the mass airflow sensor appeared when I was trying to clear the memory.
Since the car was parked outside that night, I suspected damage caused by a weasel.
At first glance, I couldn't see anything.
With so many errors suddenly appearing overnight, it occurred to me that...
"that the control unit is defective, as some parts are showing errors."
were replaced. For example, the mass airflow sensor, the intake air temperature sensor, and the electronic stability program (ESP).

Can someone tell me if my assumption is correct (plural)?
Or perhaps another idea, before I embark on a massive cable harness measurement project.
"to carry out" or "to perform" or "to execute".

Thank you in advance.

Best regards, Maximus1604.

hi,
As silly as it sounds, a mobile phone could be the cause of such phenomena!
This actually happened to me about 5 years ago!
While I was on a trip in the countryside, I received a call on my mobile phone.
It was in the T4, on the dashboard.
At that very moment, the preheating light started to blink.
So, I called Volkswagen, completely unaware at the time.
When they checked the storage device with the reader, various errors were detected, but they didn't seem to be related to each other in any meaningful way.
Error memory cleared and driving continued.

So, why couldn't a strong electromagnetic field be the cause in your case as well?

best regards, leo

Hi,

Thank you for your reply, but the errors cannot be deleted.
They remain in memory and have not been accessed.

Regards, Maximus.

Wow, the search function is really cool...

Okay, I'm ready. Please provide the German text you want me to translate.

leo_b wrote:

hi, As silly as it sounds, a mobile phone could be the cause of such phenomena! So, why couldn't a strong electromagnetic field be the cause in your case as well?

EMC measurements should not have been performed only recently. That's quite something .

Or water ingress into the control unit .

Nebelwerfer_TDI wrote:

Or water ingress into the control unit

It could also be a good thing. In any case, the ground connection for the sensors is missing (short circuit to the positive terminal).

Hi everyone,

First of all, thank you for the answers.

Okay, so today I'm working with individual components (e.g., mass airflow sensor, fuel temperature sensor, etc.).
Measured and checked the wiring for continuity, no errors found.
It doesn't seem to be water, otherwise the errors would have been cleared by now.
I couldn't find anything on the circuit board of the control unit either.
Unfortunately, it seems like the problem lies with the control unit. The VW dealer wants 1047 euros to fix it.
"I'm looking for one of those. Does anyone happen to know of any dealers where I can get it for a cheaper price? The ones I know are asking 599, which is okay, but unfortunately, they don't have any in stock."
in stock.

Regards, Maximus.

Hi,

Before you throw away the control unit, you can send it to me. I can take a look and see what can be done and whether it can be repaired.

Best regards, Rainer.

What is the part number of the faulty control unit?

Try measuring the ground connection in the engine wiring harness first. A broken wire there could have the same effect as a burnt-out circuit.

Hello!
Have you gotten any results from the control unit yet?
I just have a Sharan TDI with a 1Z engine from 1996, and it's exhibiting the exact same symptoms.
I've been working on this thing for three days now. My last resort is still the control unit.
Do you need to register a new or used car with the immobilizer system?
I would appreciate any answers.
0172/3287974
or [email protected]
Best regards, Rocco.

The problem here, again, was a short circuit in the circuit board within the control unit.
Bridge soldered, error cleared, all good.
What still worries me is: What caused the circuit board trace to fail?
Short circuit in the wiring harness of the tailgate, possibly, or the brake light switch, or both?
I'm definitely very glad that the thing is working again .
Best regards, Rocco.

I'm definitely glad that the thing is working again .

Did you, or did any of your employees, cause the errors?